Heidi Conner tells The (Arlington Heights) Daily Herald the doe came to rest in the middle of the West Dundee family's Chevy on Sunday. She and her four children were traveling about 70 mph on the Jane Addams Tollway.
She says the accident was bizarre, adding "nobody can believe this deer fell from the sky."
Illinois State Police say witnesses reported seeing the deer jump from an overpass.
Conner says the crash totaled the van and caused minor injuries, but says the way the deer landed on the vehicle was "a miracle in itself."
Police say the animal died.